Parallel-ruler.



I PATENTED JUNE 19, -1906;

- I. M. HoPsTAD.

PARALLEL RULER.

:APPLICATION FILED DBU.26. 1905.

. ll l mw A TTOH/VE YS UNITED srnrns APATENT onnron.

ISAK MYI-IRE I-IOFSTAD, OF WRANGELL, DISTRICT OF ALASKA. I PARALLEL-RULER.

Specification of Letters Patent.

Patented June 19, 1906.

Application filed December 26,1905.' Serial No. 293.256.

To aIZZ wham it mayconcern..d

. Be it known that I, IsAK MYHRE HoFs'rAD, a citizen of the United States, and a resident of Wrangell, in the District of Alaska, have invented a new andlm roved Parallel-Ruler, of which the following 1sl a full, clear, and exact description. V- l The invention relates to drafting, and its object is to provide a new and improved parallel-ruler more especially designed for the use of mariners, draftsmen, and other persons and arranged to prevent slipping on the chart or drawing and to allow accurate ruling from one place to another-for instance, when laying out a course on a map and moving the instrumeit overto the com ass.

- The invention consists of nove features and parts and combinations of the same, which will be more fully described hereinafter and then pointed out in the claims.

-A practical embodiment of the invention is represented in the accompanying drawings, forming'a part of this s ecifieation, in which similar characters of re erence indicate corresponding parts in all the views. i .a v

Figure 1 is a plan view of the improvement. Fig..2 is an enlarged sectional side elevation of one end of one of the cylinders. Fig. 3 is a like view of the other end of the cylinder, and Fig. 4 is an enlarged transverse section of the improvement.

The parallel members of the ruler are in the form of rollers or cylinders A and A', preferably made of glass or other transparent material, and each of the said cylinders A and A is provided at its ends with bands B, ofV rubber or other material, adapted to roll on the map, chart, or drawing Without danger of slipping. In the cylinders A and A are arranged pistons C and C', of which the piston-rod C2 of the piston C extends centrally through a bearing D, secured in one end of the cylinder A, the outer end of the piston-rod C2 terminating in an L-shaped extension C3, having a head C4 engaging a bearing D secured in one end of the other cylinder A. (See Figs. 1 and 2.) In a like manner :the piston C in the cylinder A has its piston-rod C4L extending through a bearing D2, secured in the end of the cylinder A opposite the one carrying the bearing D', and

the outer end of the said piston-rod C4 terminates in an L-shaped extension C5, having a head similar to the head C4 and engaging a bearing D3, iixed in the en'd of the cylinder A opposite the one carrying the 'bearing D.

piston-rods C2 and C4 are preferably provided with suitable handles E, adapted to be vtaken hold of by the operator for conveniently rolling the parallel-ruler over the map, chart, drawing, or the like.

. By the arrangement described the cylinders A and A can be conveniently adjusted in the direction of theirlength, at the same time maintaining their parallelism, and the cylinders can be conveniently and accurately rolled over the drawing, chart, or map without danger of slipping, owing to the arrangement of the rubber bands B at the ends of the cylinders.

The cylinders A and A are preferably provided with longitudinally-extending guidinglines F, etched or otherwise formed on the outer surface of the cylinder'A andpreferably colored-say red-so as to be readily discernible. On the lines F may be arranged graduations, indicating. miles, kilometer, or other linear measurements.

The parallel-ruler shown and described is very simple and durable in construction, can be cheaply-manufactured, and by having the cylinders A and A made of glass the user is readily enabled to view lines on the chart or map directly under the cylinders.

Having thus described my invention, I

l Patent- 1. A parallel ruler, comprisinga pair of transparent cylinders, and means for retaining said cylinders' in parallelism and permitting movement of the cylinders longitudinally with respect to each other.

2. A parallel-ruler, comprisinga pair ofA parallel cylinders, and pistons mounted to slide therein, the piston-rod of the piston in one cylinder being connected with the other cylinder. 3. A parallel-ruler, comprising a pair of glass cylinders having bearings in their ends, pistons 'movable in the said cylinders, and piston-rods for the said pistons, the pisv ton-rod in one cylinder extending through 'one of the bearings thereof, to engage a bearing in the other cylinder.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.I ISAK MYI-IRE HOFSTAD.

Witnesses:

WM. M..TAYLOR, F. W. CARLYON.

IOO 

